Isuzu N-Series. Manual - part 1049

CAB AND CHASSIS ELECTRICAL 8-301

4-2. Even when the Tank Is Filled Up with Fuel, the Needle Does Not Reach “F”

• WHEN INSERTING AND PULLING OUT THE

CONNECTOR  J-28  OF THE FUEL TANK UNIT
SEVERAL TIMES, DOES THE POINTER OF THE FUEL
GAUGE STAY AT THE SAME POSITION?

• DISCONNECT THE CONNECTOR OF THE FUEL TANK

UNIT 

• CONNECT THE FUEL TANK UNIT HARNESS SIDE

CONNECTOR 1  J-28  AND 3  J-28  WITH A LEAD
WIRE

• WHEN THE STARTER SW IS TURNED ON, DOES THE

NEEDLE OVERSHOOT TO "F" AFTER ABOUT 5
MINUTES?

• IS THERE A BROKEN CIRCUIT IN THE PRINTED

CIRCUIT OF THE METER ASSEMBLY?

YES

NO

REPLACE THE PRINTED
CIRCUIT BOARD

CHECK THE FUEL
GAUGE AND REPLACE
IT IF FOUND
ABNORMAL

YES

YES

NO

YES

• IS THE RESISTANCE

VALUE OF THE FUEL
TANK UNIT NORMAL?

NO

REPLACE THE FUEL
TANK UNIT

• REMOVE THE FUEL TANK UNIT

• DOES THE FLOAT ARM OPERATE SMOOTHLY?

NO

REPAIR A POOR CONNECTION AT THE CONNECTOR
OF THE FUEL TANK UNIT

N8A0312E

8-302 CAB AND CHASSIS ELECTRICAL

4-3. When the Tank Is Not Full of Fuel, the Needle Overshoots (or Goes Up To “F”)

• DISCONNECT THE CONNECTOR OF THE FUEL TANK

UNIT

• WHEN THE STARTER SW IS TURNED ON, DOES THE

NEEDLE STILL POINT TO "F"?

• IS THE CIRCUIT BETWEEN THE FUEL TANK UNIT

AND THE FUEL METER NORMAL?

YES

NO

NO

REPAIR A SHORT
CIRCUIT IN THE
CIRCUIT

REPAIR OR REPLACE
THE PRINTED CIRCUIT
BOARD

CHECK THE FUEL
GAUGE, AND REPLACE
IT IF NECESSARY

• IS THE PRINTED

CIRCUIT OF THE
METER ASSEMBLY
GROUNDED
SECURELY?

• ARE THE RESISTANCE VALUES OF THE

FUEL TANK UNIT AT "E" AND "F" POINTS
NORMAL?

YES

YES

YES

NO

REPLACE THE FUEL TANK UNIT

NO

• REMOVE THE FUEL TANK UNIT

• DOES THE FLOAT ARM OPERATE SMOOTHLY?

N8A0313E

CAB AND CHASSIS ELECTRICAL 8-303

5. Warning/indicator Light
5-1. When the Parking Brake Lever Is Pulled, the Indicator Light Does Not Light Up

5-2. Even when the Parking Brake Lever Is Released, the Indicator Light Does Not Go Off

N8A5377E

N8A5378E

8-304 CAB AND CHASSIS ELECTRICAL

5-3. While the Engine Is Operating, the Oil Pressure Warning Light Does Not Go Off

5-4. Even when the Fuel Tank Is Full with Fuel, the Fuel Warning Light Lights Up

• IS THE ENGINE OIL PRESSURE NORMAL?

• WITH THE OIL PRESSURE SWITCH CONNECTOR  J-8

DISCONNECTED, DOES THE WARNING LIGHT GO
OFF?

• WHILE THE ENGINE IS OPERATING, IS THERE

CONTINUITY BETWEEN THE OIL PRESSURE SWITCH
CONNECTOR  J-8  AND THE BODY GROUND?

YES

YES

NO

NO

NO

REFER TO THE "ENGINE" SECTION

REPAIR A SHORT CIRCUIT BETWEEN 1  J-8  AND 1 

B-52  (METER)

REPLACE THE OIL PRESSURE SWITCH

N8A0316E

• WHEN THE FUEL TANK UNIT CONNECTOR  J-28  IS

DISCONNECTED, DOES THE WARNING LIGHT GO
OFF?

• IS THE FUEL TANK UNIT NORMAL?

YES

NO

NO

REPAIR A SHORT CIRCUIT BETWEEN THE FUEL
TANK UNIT HARNESS SIDE CONNECTORS 2  J-28
AND 10  B-51  (METER)

REPLACE THE FUEL TANK UNIT

N8A0317E